Art of separating metals from speiss.



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ALBION awannans, or RIVERTON, NEW J BRIGHTON, NEW YORK, ASSIGNORS T ERYVSEY, AND ROBERT C. s'rANLEY, or NEW 0, INTERNATIONAL NICKEL COMPANY, OF

No.'ooo,454.

Specification o1 I'atent.

. Patented Oct. e, 1908.

Application filed February 16, 1907. Serial No. 357,720.

New Bri hton, county of Richmond, and

State of. ew York, have invented an Implrovement in the, Art of Separating Metals om Spe1ss, of which the following is a specification.

The purpose .of our invention is to provide a cheap and effective means for the separa-- tion of copper, nickel, cobalt and silver from arsenic and other elements with which they are associated in speiss or other arsenical matte, and to selparate the silver from the co per, nickel, co alt and iron. The processes Ieretofore employed for this purpose have been difficult and, to a large extent wasteful, but our process reduces the cost to a very small amount and, provides means by which the values are recovered with little or'no waste.

Our invention is applicable to matte containing nickel, cobalt, silver and iron, whether CO or is contained therein or not.

e first eliminate the arsenicfrom the other metals of the speiss. This we accomplish by roasting the speiss or concentrate in a calcining furnace at a cherry red heat until arsenical fumes cease to beliberated therefrom. We then take the calcined material, grind it with carbon tpreferably inthe form of roast the mixture in a reducing atmosphere, which reduces the arsenical compounds into arsenids, and we then subject the mixture to an oxidizing roast which liberates arsenic fumes. The alternate reduction and oxidation are re-' peated' in this manner until fumes of arsenic.

' cease to be liberated. If this 0 eration is carried to the limit, material w 'ch originally contained 35 per cent. arsenic, 16 per cent. nickel, 25 per cent. cobalt, and 10 per cent. iron, will contain about 4 percent. of arsenic. To eliminate this'residue we'preferably proceed as follows: We mix the material wlth nitrate of soda and soda ash which are employed preferably in the proportion of 1 Lpart of nitrate of soda and two parts of a ash to one part of arsenic contained in the compound, and we then calcine the mixture in a furnace, preferably at a cherry red heat, untiLall of the arsenic is converted'into arsenate of soda. Any of the other soda salts, such as caustic soda, carbonate of soda, may be used, which when heated will combine with the arsenic to form arsenate of soda. We then withdraw the material from the furnace and wash it, preferably in a washtank, althou h we may employ mechanical stirrers or a'nltering apparatus, until the arsenate of soda has been dissolved. We then prefer to concentrate the solution by evaporationand remove the arsenate of soda by crystallization, as it is a valuable product.-

The undjssolved material is separated and dried with heated air, and by the treatment above describedv the ercentage of arsenic can be. brou ht to as ow as one-half of one .per cent.

T e residual material consists of oxids of copper, nickel, cobalt and iron, together with other oxids such as silicon, aluminum and calcium, and metallic silver, but it is substantiall free-from arsenic or arsenate of soda. T e material is then dissolved in hydrochloric acid, which is referably concentrated, and inorder to o tain the most rapid and effective solution we prefer to perform it in a revolving cylinder under ressure and with the influence of heat. We aveobtained suitable results with an internal pressure in the cylinder of about 60 to pounds,

.the acid being heated to about 135 F. and

the treatment continued from six to eight hours. The hydrochloric acid dissolves the chlorids of the several metals except the silyer, only a art of which will disso ve there- In, the resi ue remaining undissolved as a chlorid. The undissolved silver and silver chlorid are allowed to settle for subsequent removal and smelting, and the solution is then drawn off and treated for the removal of the iron. For this purpose we prefer to mix the solution with an al ali, preferably caustic lime, which precipitates the iron as a hydrate and also removes the last of the arsenic, but holds the silver in solution. The solution, freed from iron and still acid, is

treated for the removal; of copper and silver by passing sulfureted hydrogen through it, whlch preci itates the copper and silver as sulfids; or t e solution ma be passed-over copper or zinc, on which t e silver will d e-' posit by cementin The preclpltate of S11- ver and co per su ds, or cemented silver, may be was ed and collected and smelted in a furnace. After this treatment the solution contains chlorids of nickel and cobalt, and

- can be treated by known methods for the 10 with a. sodium compound capable of combining with the arsenic to form an arsenate, thus convertin the arsenic into arsenate of soda; substantlall as described.

, In testimony w ereof, we have hereunto set our hands.

ALBION J. WADHAMS. ROBT. C. STANLEY. Witnesses:

GEORGE H. SONNEBORN, ANNA E. WALLACE. 

